Westsiders blast past it on their way to concerts at the Gorge Amphitheatre. Central Washington residents often overlook it on their way to Spokane or other points east.

And that’s too bad, because this 7,470-acre park state park contains the aftermath of two cataclysmic geologic events: massive lava flows and flooding on an unimaginable scale.

Some 15 million years ago, this now-stark landscape was a forest of oak, maple and ginkgo. But when the earth opened in the area of what is now Idaho, vast flows of lava rolled westward, burying animals and entire trees.

Mud and water protected some of the trees as they were entombed under the hardening lava.

Over time, water carried minerals that replaced the vegetation while retaining its shape and characteristics, such as bark and tree rings.

Today, the remains of these trees can be viewed from a series of trails leaving from the state park visitors center off the Old Vantage Highway.

Another set of rocks scattered through the area tell of an entirely different event, the Ice Age Floods, which took place 12,000 to 18,000 years ago. Huge walls of water repeatedly washed across Central Washington when giant ice dams gave way, releasing a lake of water that covered a good portion of modern-day Montana.

Embedded in huge chunks of ice that were carried along by the floods were rocks, called erratics. Erratics can be found scattered across the park. The rocks, while covered with lichen, come from Montana and are different from the basalt that otherwise found in the region.

The Ginkgo Petrified Forest State Park is open during the summer from 6:30 a.m. to dusk. Winter months, defined as Nov. 1 through March 1, the park is open from 8 a.m. to dusk on weekends and holidays only.